The present invention relates generally to the field of angioplasty and angioplasty catheters. More specifically, the present invention relates to methods and apparatus for minimizing the occurrence of restenosis following dilatation of a narrowing in a body lumen.
Percutaneous transluminal coronary angioplasty (PTCA), a procedure for treating a patient having a stenosis or constricted region in a coronary artery, has become a widely accepted therapeutic alternative to coronary arterial bypass surgery for many patients. PTCA increases the diameter of the lumen by radial expansion, such as through the use of a dilatation balloon. In the appropriate circumstances, PTCA has a variety of advantages over coronary bypass surgery, including reduction in morbidity, and avoidance of immediate post-operative discomforts and recovery period. Balloon dilatations are also accomplished in a wide variety of other locations in the body to restore patency to an undesirably constricted lumen.
Notwithstanding the advantages of balloon dilatation over more invasive alternatives, balloon dilatation often does not result in a permanent treatment of a stenotic site. Rather, a renarrowing or restenosis of the treatment site is often observed at varying lengths of time following the initial procedure. This is particularly true in the case of PTCA. Patients experiencing a restenosis must thereafter be evaluated for a subsequent medical procedure, such as a further PTCA dilatation or alternative therapy.
Accordingly, there remains a need for a method of minimizing the occurrence of restenosis in a dilated region of body lumen. Optimally, the method would either lengthen time between dilatation procedures, or prevent entirely the need for a subsequent dilatation procedure.